Dayana Muzziotti Gil, Alessandra Adessi, Andrea Sanchini, Laura Dipasquale, Giuliana d’Ippolito, Angelo Fontana and Roberto De Philippis
Department of Agrifood Production and Environmental Sciences (DISPAA), University of Florence, Florence, Italy
TThe sequential combination of Dark and Photo-fermentation is a promising process for the production of biohydrogen. It is possible to approach the theoretical maximum yield of 12 mol of H2 (mol glucose)-1. In this study, the substrate tested for the combined process was artificial sea water supplemented with glucose. The aim of this research was to test the H2 photoevolution performance of Purple Non Sulfur Bacteria (PNSB), specifically Rhodopseudomonas palustris 42OL, growing on two synthetic spent media deriving from the dark fermentation process: ASW (Artificial Sea Water, 40 g/L of sea salts) and DASW (Diluted Artificial Sea Water, 10 g/L sea salts), both supplemented with glucose (5 g L-1). The DASW spent medium showed to be the best for Rp. palustris 42OL because, H2 was produced and showed a high mean H2 production rate. Furthermore, a yield of 4.74±0.37 mol H2 per mol of glucose was obtained. It has to be stressed that, this yield is much higher than typical yields obtained in the single process operating by Rp. palustris. As it seems from the results, it was possible to obtain H2 with a high yield from a saltrich medium, which usually is not suitable for growing PNSB.